1. Field of the Invention
The present invention relates generally to a drain plug apparatus for use with boats, and more specifically to a dual seal drain plug assembly including a self-closing shutoff valve that is designed and configured to enable water to exit when the boat is out of the water and will prevent water from entering the boat after launch.
2. Description of the Prior Art
Most boats include a drain plug that is located on the lower portion of the transom. The purpose for this plug is to enable water to escape from the boat's bilge. Thus, when the boat is removed from the water, the user can remove the plug and allow all standing water to be removed. Generally, boats are removed from the water after each use and stored on a trailer, boatlift, rack in a marina, or the like. As is customary, the plug is left out of the boat to keep the bilge dry while in storage.
The most popular drain plug utilized today is a threaded plug that screws into a hole that is located at the lower end of a boat's transom. The vast majority of boat manufacturers use a ½ inch externally threaded brass plug which screws into a matching brass female fitting that is affixed to the existing drain hole. A few boat manufacturers incorporate plugs with non-standard threads, or use plugs of other diameters or materials. Others will incorporate the exterior of the plug with non-threaded rubber material. Such plugs fabricated from non-treaded rubber are known as a stopper.
In all cases where a plug or stopper is employed, operator intervention is required to dislodge and reinstall the particular device. Though efficient, this conventional form does cause plugs to often be misplaced, lost, or even stolen. Another problem associated with the conventional plug is that there is a chance for the plug to be “cross-threaded” when reinstalled. This “cross-threading” can cause leakage. The most serious problem with conventional drain plugs is that the operator sometimes forgets to install them prior to launching the boat. When this occurs, the boat will rapidly fill with water resulting in significant damage, potentially sinking the boat, and inherently placing the passenger's safety in jeopardy.
As such, devices have been developed that will reduce the requirement for operator intervention. For example, U.S. Pat. No. 4,019,454 discloses a ball assembly that will swing to seal the existing hole when the boat is not in movement. U.S. Pat. No. 4,198,918 discloses a plug that includes a spring-biased plunger that will be released (in a closed state) by the action of a float mechanism when the boat is lowered in the water. U.S. Pat. No. 5,385,108 discloses a plug that is hingedly secured to a cap and will swing shut to seal the device when submerged.
Many other devices exist on the market that utilize a ball check valve that is either mounted inside or outside the transom drain hole. Still other devices currently marketed use flexible rubber flaps that are shaped to allow water to flow out of the drain but will seal when water attempts to flow in the reverse direction. Though somewhat successful, each method does have a single failure point in the sealing mechanism. The seals can fail if contaminated by common bilge trash (weed, sand, leaves, bugs, or the like). Still other devices have been developed to provide a warning when the plug is removed, for example see U.S. Pat. No. 4,542,373 and U.S. Pat. No. 4,843,376. Though efficient, these devices tend to be costly; difficult to install, and depend on battery power and proper wiring, which are both subject to failure.
Though bilge pumps are installed on most water vessels larger than 16 feet in length to automatically remove excess water from the boat's bilge, these pumps will only activate when the water level in the boat reaches a pre-set level. These particular pumps are designed to effectively remove water that enters the boat due to rain, slow leaks, wave action, or the like. The pumps unfortunately cannot keep up with constant, high-volume in-flow water, such as what occurs when the plug is not replaced in the drain hole of a boat. In addition, these pumps can burn out if they remain operating for an extended period of time, thereby defeating its purpose. Further the pumps are inactive when there is a power failure.
In my earlier Patent, U.S. Pat. No. 6,634,312, I describe a one-way self closing drain plug assembly having two or three chambers wherein one contains a self-closing shutoff valve and the other chamber(s) contain a check valve(s). This invention achieves the intended purpose to efficiently and adequately enable water to be removed when desired by a boat operator and automatic closure to prevent water from entering the vessel when the boat is moving in the water. However, its multi-chamber design is expensive to manufacture, its single-seal shut-off valve seal has a single point of failure, its strainer filter design is difficult to install, and the shut-off valve locking mechanism is not intuitive to operate.
Accordingly, it is seen that there is a need to provide a drain plug assembly that will efficiently and adequately enable water to be removed when desired by a boat operator and one that will automatically close so as to prevent water from entering the vessel when the boat is in water. Moreover, the assembly should provide for low cost construction, improved reliability, ease of installation, and intuitive operation.
As will be seen, the present invention achieves its intended purposes, objectives and advantages by accomplishing the needs as identified above, through a new, useful and unobvious combination of component elements, which is simple to use, with the utilization of a minimum number of functioning parts, at a reasonable cost to manufacture, assemble, and test and by employing only readily available material.